<html>
<head>
    <link rel="stylesheet" href="about:blank" type="text/css">
</head>
<body>
    <p>If the canvas below is black, then we managed to draw before loading stylesheets. Hooray!</p>
    <canvas id="mycanvas" width="400" height="200"></canvas>
    <script type="application/x-javascript">
        var canvas = document.getElementById("mycanvas");
        canvas.getContext("2d").fillRect(0, 0, canvas.width, canvas.height);
    </script>
</body>
</html>
